Abstract HIV+ individuals are several thousand times more likely to be diagnosed with Kaposi sarcoma, 70 times more likely to be diagnosed with non-Hodgkin lymphoma, and five times more likely to be diagnosed with cervical cancer than uninfected people. They are also more likely to be diagnosed with anal, liver, and lung cancer, and Hodgkin lymphoma. African Americans are disproportionately affected by HIV and cancer. They represent 13% of the population, yet accounted for 43% of HIV cases in 2014. NCI recommends antiretroviral therapy (ART) as a key cancer prevention strategy among HIV+ individuals, yet many HIV+ people, especially African Americans, have difficulty adhering to ART. According to NCI, regular screenings and a healthy lifestyle may also help reduce cancer rates? but only if used consistently. A growing literature of randomized controlled trials has demonstrated mhealth to be successful for promoting cancer prevention, healthy lifestyle behaviors and medication adherence?including among African Americans. However, no cancer prevention mhealth intervention has yet been developed that targets HIV+ African Americans, despite this group being disproportionately affected by BOTH cancer and HIV. To address this critical gap, the research team, which includes a health psychologist and experts in oncology, infectious disease, health disparities, and pharmacology, will develop a culturally-sensitive mhealth intervention that includes a patient app and care provider team (CPT) platform to promote cancer prevention behaviors among HIV+ African American adults. This research will be guided by three specific aims: 1) Develop an individually-tailored, culturally-sensitive mhealth intervention, comprised of a patient app and CPT platform to promote cancer prevention behaviors among HIV+ African American adults. 2) Implement 12-week pre-post test design pilot to evaluate short-term effectiveness for promoting cancer prevention behaviors, i.e. self-efficacy for healthy eating, self-efficacy for walking, cancer screening intention, and ART adherence among HIV+ African Americans. 3) Evaluate feasibility. At 12 wks, we will evaluate feasibility via focus groups with all pre-post participants and interviews with CPT members involved in implementation. The primary and secondary hypotheses are that HIV+ African American adults who receive tailored cancer prevention texts plus daily pill reminders for 12 weeks will show 1) greater self-efficacy for healthy eating and greater self-efficacy for walking and 2) greater cancer screening intention and greater ART adherence at 12 weeks compared to baseline. Long-term, if proven to be effective in a Phase II SBIR application, the proposed research will help to reduce the cancer rates and increase early diagnoses of cancer among African Americans who are HIV positive, while simultaneously improving ART adherence rates.